Backdraft Cobra AUS - The search for reliability

[spookypt]

After a massive day yesty I got it in. Apart from a leak around the thermostat and some mods to make it all work it went in all ok. But I NEVER want to have to install those headers again argh.

Break in oil is in a quick 20 sec start to get a base set up for dyno satdy.

[Tenrocca]

Looking good Spook. Needs gold wheels though.

[byroncobra]

Matt, despite all the jibes, smart arse comments and cynically intoned comments from forum buddies you've gotta be the most tenacious bloody cobraphile out there.
That car has had that many incantations/modifications that you could have
built 10 of the mongrels.
I rarely click on the clubcobra site these days, the only thing that keeps me coming back to it to see what the fluck you're up to next with old #6
I hope with all my heart that that car does all that you expect of it.....you deserve it mate

[spookypt]

I'm thinking this direction now but in GOLD of course!

[spookypt]

Big weekend just passed.

Friday night all loaded and ready for dyno day.

[spookypt]

OK so Dyno is done. Firstly to discount a few myths.

My old engine, yes the ear cracker, no doubt could have made stout horse power at 9000rpm as it was designed (sorta). Running 116 Oct race gas at about $8 a litre and 13.5 - 1comp made for a great show stopper but for actual drivability on Oz circuits it was a very expensive all show no go engine in reality.

After its initial failure and rebuild keeping with the American spec and basically a refresh it pulled 484HP at 7800rpm. No doubt there was more in it but at a cost. Despite me running this engine under 8000rpm for its recent life it was an expensive super high maintenance engine which in the end I HATED!

Here's its dyno pull from a few years ago.

[spookypt]

So a new engine was formulated. I kept the manifold, reported it a bit more, kept the heads and the rest was new. It has some very very nice parts in it but it was built to last and to have fun in, run in a safe zone and just drive.

Its running 98 Oct pump fuel and 10.5 - 1.

So the dyno day started at 8am and finished at 3.30 on Satdy. Man we sorted out some issues that no one in the last 7 odd years seemed to address. Simple things like the radiator cap not holding pressure, the dizzy advance was not fixed and its springs were so soft it was virtually NOT working. We had the jets in and out about a dozen times to get the mix right, sorted the metering blocks, ran both MSD boxes to ensure we had the same tunes and read the spark plus to ensure we had good advance. Despite previous testing and paying for an alternator over-hall it ISNT working properly only pulling 12.8v at 7000rpm so its gone to get fixed. (that was a bit frustrating after paying for its repair once already)

In the end we can (if one wanted to) increase the advance a bit more and rpm and chase to E85 and or fuel injection and get more but why would you???

The net result was an engine that idles beautifully, starts first go, is 10.5 - 1 and runs on pump fuel.

You be the judge but Im happy with the result.

[spookypt]

Now I have along list of small things to start to put it all back together for the first A Series round.

Plenty of time. New rad cap is ordered and alternator is already at the shop getting new bushes etc which seemingly haven't been done for a very very long time!~Hmmm

[Chris L]

I'd call the a step forward Spooky, should help you sleep easier at night. Well played.
Cheers
Chris L

[lovehamr]

Looks like that's going to be a great lump to play on the track with! I do have a question about the new dyno readout, what's with the "road speed" rather than engine RPM?

[spookypt]

Originally Posted by lovehamr

Looks like that's going to be a great lump to play on the track with! I do have a question about the new dyno readout, what's with the "road speed" rather than engine RPM?

Dunno. Just the read out I got at the time I guess.

[spookypt]

I haven't gone to town on the door hinge as Im running out of time but its fully functional and will do for now. I'll make it visually pretty in the off season. Big thumbs up to WILL from ICCARS who supplied the hinge. Worked a treat!





First corner scale set up with everything done. Now to adjust it all to make it work.

[Gav]

are those weights with or without you in it?
If you are in it, they are pretty good!

[spookypt]

Hey Gav, no that's without my barge a$$. Add 88kg.

Ive improved the static by getting the set up better with correct tyre pressures, levelled and shimmed corner weights etc.

BDRUSA want me to run 2mm toe in fr and rear
- 2.5"camber fr and rear
- 5 degree castor

Im learning as I go on this but having squared the car up and running string lines etc my right front had 20mm toe out! LOL

I think its in real need of some tuning. Ive ordered a camber gauge and a C spanner today so I'll do a final set up and balance in the weekend.

Learning curve overrev atm

[albanycobra]

Then send those scales to me....88kg I can only dream...lol.

[spookypt]

All you need to do is just stand on them with 1 foot Dave.

[stephen low]

Just a question about setting up the corner weights.

Am I right in presuming that it would be preferable to do all the set up with the driver in their seat?

Then the car is balanced under normal operating conditions.

Or does that extra 60 - 120 kgs (I'll say 80 for me!!) not cause that much effect?

[spookypt]

Stephen IMO always best to set your car up as you would have it when driving. That includes driver, fuel, water, tyre pressures etc etc.
Its quite an art it seems and you need to work through it with patience.
Ive been instructed to do my general set up (by a well respected supercar guy) as follows
- Ride height using corner weights as its driven
- Castor
- Camber
- Toe
Hope that helps.

[Gav]

Corner weighting is speculative at best with most cars.
If you were serious you would build the car with weight distribution in mind, like battery on the opposite side to the driver for instance.
You do need to take into account the weight it will run on the track and just try to get things as close as you can.
Mine used to be about 20kgs out across the back and 40 across the front with me in it.
The cross weight was around 50.9%.
Could have been better if more thought went into it while building but that would have required scales the whole time.

[gjkrv8]

Re Corner weighting - would my front right locking up much easier than the left be a symptom of unbalanced corner weights - or just a crappy driver :-)